| 摘要 |
PROBLEM TO BE SOLVED: To perform appropriate switching control on an output current flowing through a load.SOLUTION: A load drive device 1 includes: a switch N1, a driver 14 for controlling on/off the switch N1 in accordance with SWON; a comparator 17 for comparing Vdet1 with Vth and generating IPEAKDET; an ADC 19 for converting Vdet1 to ADCOUT; a DAC 18 for converting IPEAKSET to Vth; and a logic section 12 for outputting SWON and IPEAKSET in response to the input of IPEAKDET and ADCOUT. The logic section 12 includes an arithmetic circuit 122 for calculating Y1 by using an arithmetic expression given by Y1=AVE×α+&Dgr;×Ton/2 (where, Y1: a signal value of IPEAKSET; AVE: an average current setting value of an output current; α: an adjustment factor for AVE; Ton: an on period; &Dgr;: a change rate of AVCOUT). The arithmetic circuit 122 determines α in accordance with arithmetic mode setting signals ISO and PFC. |
